Measuring the level of homocysteine, an amino acid in the blood, can provide predictive insights into an individual’s risk of developing obstructive sleep apnea, a disorder characterized by repeated interruptions in breathing during sleep due to the relaxation of throat muscles. Researchers at the Sleep Institute and the Federal University of São Paulo (UNIFESP) in Brazil, with the support of FAPESP, have determined that this simple blood test not only predicts the likelihood of the disorder but also assesses whether a patient with mild or moderate apnea is likely to progress to severe apnea. These findings were published in the European Archives of Oto-Rhino-Laryngology.
Monica Levy Andersen, a professor at UNIFESP and the study’s senior author, noted the uncertainty about whether apnea causes the rise in homocysteine levels or vice versa. She suggests that the relationship might be bidirectional and recommends including the homocysteine test in routine medical examinations for people over 40. This simple and cost-effective test, especially under Brazil’s public health system (SUS), could provide crucial data on this correlation.
Cardiologists have long been concerned with homocysteine due to its potential to cause cardiovascular problems. Elevated levels of this amino acid, known as hyperhomocysteinemia (more than 15 micromoles per litre), can lead to blood vessel damage and increase the risk of coronary diseases, thrombosis, and strokes. Vanessa Cavalcante-Silva, a postdoctoral researcher at UNIFESP and first author of the study, explains that a deficiency in B-complex vitamins—specifically B6, B9, and B12—can predispose individuals to high homocysteine levels. Therefore, dietary intake of these vitamins or supplementation could be a strategy to regulate these levels.
The data for this study was derived from the Epidemiological Study of Sleep (Episono), led by Sergio Tufik, a professor at UNIFESP, which has been examining the sleep quality and the effects of sleep disorders on the residents of São Paulo for over fifteen years. Preliminary findings from 2007 showed that a significant portion of the population experienced frequent snoring and sleep apnea. These conditions not only disrupt domestic peace but also impair memory, accelerate cellular ageing, and increase the risk of several severe health issues like hypertension, diabetes, and heart failure.
In their analysis, Andersen’s team used a sample of volunteers from the Episono project who underwent polysomnography tests to measure their apnea-hypopnea index (AHI), a diagnostic tool for sleep apnea severity based on the number of breathing disruptions per hour. Initially, they diagnosed varying degrees of apnea among participants and correlated these with different blood levels of homocysteine, revealing that higher homocysteine levels were associated with higher AHI scores.
A follow-up study conducted in 2015 aimed to investigate if homocysteine levels could predict the development of apnea in participants who initially did not have the condition. The results indicated a modest but existing risk: a slight increase in homocysteine levels correlated with a slightly higher risk of developing sleep apnea over the years. Andersen highlights the clinical relevance of this finding, suggesting that regular monitoring of homocysteine could provide valuable predictive information for managing and potentially mitigating the progression of sleep apnea. This novel approach underscores the potential of routine blood tests for risk assessment and guiding effective interventions in sleep medicine.
More information: Vanessa Cavalcante-Silva et al, Homocysteine as a predictor of apnea–hypopnea index in obstructive sleep apnea: a longitudinal epidemiological study (EPISONO), European Archives of Oto-Rhino-Laryngology. DOI: 10.1007/s00405-024-08614-z
Journal information: European Archives of Oto-Rhino-Laryngology Provided by Fundação de Amparo à Pesquisa do Estado de São Paulo
